1. Field of the Invention
The present invention relates to a mutant Escherichia coli capable of enhanced L-glutamic acid production and a process for producing L-glutamic acid by fermentation. L-glutamic acid is an amino acid which is important as food, medicine, etc.
2. Discussion of the Background
Heretofore, glutamic acid has been produced by fermentation using a glutamic acid-producing bacterium belonging to the genera Brevibacterium, Corynebacterium or Microbacterium ("Amino Acid Fermentation, pp." 195-215, published by Gakkai Shuppan Center, (1986)). Other known processes for fermentatively producing L-glutamic acid employ microorganisms belonging to the genera Bacillus, Streptomyces, Penicillium (U.S. Patent No. 3,220,929) or the genera Pseudomonas, Arthrobacter, Serratia or Candida (U.S. Pat. No. 3,563,857). By these processes, L-glutamic acid can be produced with a fairly high productivity. However, in order to meet ever-increasing demand for the amino acid, a more effective and less costly process is desired.
With its fast growth and the advancement in the analysis of its gene, Escherichia coli has potential as a good L-glutamic acid-producing microorganism. However, according to published reports, Escherichia coli accumulates L-glutamic acid at only an extremely low level, not higher than 2.3 g/l (J. Biochem., vol. 50, p. 164-165 (1961)).